The present invention relates to a degreasing-cleaning method for removing paraffinic or soap-type mold releasing agents or the like from molded plastics products and other materials or articles such as glass for liquid crystals, plastic lenses, glass lenses, photo-masks, disc ceramic substrates, quartz, heads, glass for CCDs and precision machine parts.
FIG. 7A and FIG. 7B show an apparatus for use in a conventional method. The apparatus comprises a mist room 41 (FIG. 7A), and a shower room 42 (FIG. 7B). The mist room 41 and the shower room 42 each have the article W to be cleaned, as suspended from the ceiling. The article W is a motor vehicle bumper. The mist room 41 contains a liquid cleaning agent L, which is an organic solvent such as trichloroethane. The cleaning agent L is heated with a heater 43 and converted to mist, which rises and is then cooled by coolers 44 to undergo condensation. The liquefied agent L adheres to the article W. Shower heads 45 are suitably arranged within the shower room 42 for applying the same organic solvent as above, i.e., agent L, to the article W. The cleaned article W is delivered from the shower room 42 and subsequently sent to a coating process.
Also known is other method wherein city water containing an acid or alkali added thereto for use as a liquid cleaning agent is sprayed on articles for cleaning.
The method wherein an organic solvent is used as the cleaning agent has found limited use because the organic solvent poses the problem of environmental pollution, so that it is desired to develop an alternative method.
On the other hand, the method wherein the acid- or alkali-containing city water is used as the cleaning agent requires a large amount of cleaning water and therefore releases a large quantity of waste water, which results in a problem of disposal.